A LITTLE GIRL

A little girl asked her mother "Mom, how old are you?"
Her mother snapped back at her "Haven't I told you it's not polite to ask a woman her age?"
The little girl was telling her friend the story and her friend told her
"You can find out anything you want about your mother from her driver's license".
The next day, the daughter approached her mother
"Mom, I know EVERYTHING about you." Her mother said "Like what?" "I know how old you are -- you're 38. I know you weight 137 pounds, and I know why Dad divorced you". "You do, do you? Well, tell me."
The daughter looked at her mother with a sad face and said "Because you got an "F" in sex."